FIRST MID TERM TEST - 2025
10th Standard - SCIENCE
Time: 1.30 Hrs | Marks: 50
Question Paper
1. Impulse is equal to
- Rate of change of momentum
- Rate of force and time
- Change of momentum
- Rate of change of mass
2. Where should an object be placed so that a real and inverted image of the same size is obtained by a convex lens?
- f
- 2f
- infinity
- between f and 2f
3. The eye defect "presbyopia" can be corrected by
- Convex lens
- Concave lens
- Convex mirror
- Bi-focal lenses
4. Which of the following is a triatomic molecule?
- Glucose
- Helium
- Carbon dioxide
- Hydrogen
5. 1 mole of any substance contains ________ molecules.
- $6.023 \times 10^{23}$
- $6.023 \times 10^{-23}$
- $3.0115 \times 10^{23}$
- $12.046 \times 10^{23}$
6. ________ group contains the member of halogen family.
- 17th
- 15th
- 18th
- 16th
7. ________ is an important metal to form amalgam.
- Ag
- Hg
- Mg
- Al
8. The endarch condition is the characteristic feature of
- Root
- Stem
- Leaves
- Flower
9. Which is formed during anaerobic respiration?
- Carbohydrate
- Ethyl alcohol
- Acetyl Co, A
- Pyruvate
10. The body of leech has
- 23 segments
- 33 segments
- 38 segments
- 30 segments
11. State Newton's second law.
12. Match it
| PART - I | PART - II |
|---|---|
| A. Retina | Path way of light |
| B. Pupil | Far point comes closer |
| C. Ciliary muscles | Near point moves away |
| D. Myopia | Screen of the eye |
| E. Hypermetropia | Power of accommodation |
13. Why does the sky appear in blue colour?
14. Define Atomicity.
15. What is Rust? Give the equation for formation of rust.
16. Draw and label the structure of oxysomes.
17. Write the dental formula of rabbit.
18. Calculate the velocity of a moving body of mass 5 Kg whose linear momentum is 2 kg ms⁻¹.
19. Describe rocket propulsion.
20. Differentiate the eye defects: Myopia and Hypermetropia.
21. List out the properties of light.
22. Write the applications of Avogadro's law.
23. a) Name the acid that renders aluminium passive. Why?
b) What is an Amalgam? Give an example.
24. a) What is respiratory quotient?
b) Write a short note on mesophyll.
25. Calculate the mass of 2.24 L of SO₂ gas at S.T.P.
26. a) i) What are the types of inertia? Give an example for each type. (5)
ii) State Rayleigh's law of scattering. (2)
b) i) Give the salient features of "Modern atomic theory". (5)
ii) Give any two examples for hetero diatomic molecules. (2)
27. a) Differentiate the following:
i) Monocot root and Dicot root (4)
ii) Aerobic and Anaerobic respiration (3)
b) i) List out the parasitic adaptations in leech. (5)
ii) How is diastema formed in rabbit. (2)
Solutions
1. c) Change of momentum
2. b) 2f
3. d) Bi-focal lenses
4. c) Carbon dioxide (CO₂)
5. a) $6.023 \times 10^{23}$
6. a) 17th
7. b) Hg (Mercury)
8. b) Stem
9. b) Ethyl alcohol
10. b) 33 segments
11. State Newton's second law.
Newton's second law of motion states that the force acting on an object is equal to the rate of change of its momentum. Mathematically, it is expressed as:
$F = \frac{\Delta p}{\Delta t}$
For an object of constant mass 'm', this simplifies to $F = ma$, where 'F' is the force, 'm' is the mass, and 'a' is the acceleration.
12. Match it
| PART - I | PART - II |
|---|---|
| A. Retina | Screen of the eye |
| B. Pupil | Path way of light |
| C. Ciliary muscles | Power of accommodation |
| D. Myopia | Far point comes closer |
| E. Hypermetropia | Near point moves away |
13. Why does the sky appear in blue colour?
The sky appears blue due to a phenomenon called Rayleigh scattering.
- When sunlight enters the Earth's atmosphere, it is scattered by the tiny gas molecules (like nitrogen and oxygen).
- According to Rayleigh's law, the amount of scattering is inversely proportional to the fourth power of the wavelength of light ($Scattering \propto 1/\lambda^4$).
- Blue light has a shorter wavelength than red light, so it is scattered much more effectively. This scattered blue light reaches our eyes from all directions, making the sky appear blue.
14. Define Atomicity.
Atomicity is defined as the total number of atoms present in one molecule of an element, compound, or substance.
- Example 1: Oxygen (O₂) is a diatomic molecule, so its atomicity is 2.
- Example 2: Ozone (O₃) is a triatomic molecule, so its atomicity is 3.
- Example 3: Helium (He) is a monoatomic molecule, so its atomicity is 1.
15. What is Rust? Give the equation for formation of rust.
Rust is hydrated ferric (III) oxide, a reddish-brown flaky substance that forms on the surface of iron or its alloys when exposed to oxygen and moisture. It is a form of corrosion.
Equation for rust formation:
$$ 4Fe + 3O_2 + xH_2O \rightarrow 2Fe_2O_3 \cdot xH_2O $$
(Iron + Oxygen + Water → Hydrated Ferric Oxide (Rust))
16. Draw and label the structure of oxysomes.
Oxysomes, also known as F₀ - F₁ particles, are found on the inner mitochondrial membrane. They are responsible for ATP synthesis. A drawing is not possible, but the structure can be described and labelled as follows:
An oxysome consists of three parts:
- Head (F₁ particle): A spherical part that projects into the mitochondrial matrix. It contains the site for ATP synthesis.
- Stalk (F₀ connector): Connects the headpiece to the base.
- Base (F₀ particle): Embedded in the inner mitochondrial membrane and acts as a proton channel.
[Head (F₁)] --- [Stalk] --- [Base (F₀ in membrane)]
17. Write the dental formula of rabbit.
The dental formula of a rabbit is:
$$ I \frac{2}{1}, C \frac{0}{0}, PM \frac{3}{2}, M \frac{3}{3} $$18. Calculate the velocity of a moving body of mass 5 Kg whose linear momentum is 2 kg ms⁻¹.
Given:
- Mass (m) = 5 kg
- Linear Momentum (p) = 2 kg ms⁻¹
Formula:
Linear momentum (p) = mass (m) × velocity (v)
$p = mv$
Calculation:
To find the velocity (v), we rearrange the formula:
$v = \frac{p}{m}$
$v = \frac{2 \text{ kg ms}^{-1}}{5 \text{ kg}}$
$v = 0.4 \text{ ms}^{-1}$
The velocity of the body is 0.4 m/s.
19. Describe rocket propulsion.
Rocket propulsion is based on the principles of Newton's Third Law of Motion and the Law of Conservation of Linear Momentum.
- Fuel and Oxidizer: A rocket contains fuel (either solid or liquid) and an oxidizer. When the fuel is burned, it produces a large quantity of hot gas.
- Ejection of Gases: These hot gases are ejected at very high speed from a nozzle at the rear of the rocket. This creates a large downward momentum.
- Newton's Third Law: According to Newton's third law, for every action, there is an equal and opposite reaction. The downward ejection of gas (action) results in an equal and opposite upward force on the rocket, called thrust (reaction).
- Conservation of Momentum: To conserve the total linear momentum of the system (rocket + ejected gas), the rocket moves forward (upward) with a momentum that is equal in magnitude and opposite in direction to the momentum of the ejected gases. As more gas is ejected, the mass of the rocket decreases, causing it to accelerate further for the same amount of thrust.
20. Differentiate the eye defects: Myopia and Hypermetropia.
| Feature | Myopia (Near-sightedness) | Hypermetropia (Far-sightedness) |
|---|---|---|
| Vision Defect | Can see nearby objects clearly, but distant objects appear blurry. | Can see distant objects clearly, but nearby objects appear blurry. |
| Image Formation | The image of a distant object is formed in front of the retina. | The image of a nearby object is formed behind the retina. |
| Cause | The eyeball is too long, or the focal length of the eye lens is too short. | The eyeball is too short, or the focal length of the eye lens is too long. |
| Correction | Corrected using a concave lens of appropriate power. | Corrected using a convex lens of appropriate power. |
21. List out the properties of light.
The main properties of light are:
- Rectilinear Propagation: Light travels in a straight line in a uniform medium.
- Reflection: Light bounces back when it strikes a polished surface.
- Refraction: Light bends when it travels from one medium to another.
- Speed: Light travels at a very high speed, approximately $3 \times 10^8$ m/s in a vacuum.
- Dispersion: White light splits into its constituent seven colours (VIBGYOR) when passed through a prism.
- Scattering: Light is deflected in various directions upon striking particles in a medium.
- Interference & Diffraction: Light exhibits wave properties like interference (superposition of waves) and diffraction (bending around obstacles).
- Dual Nature: Light exhibits both wave-like and particle-like (photons) properties.
22. Write the applications of Avogadro's law.
Avogadro's law states that equal volumes of all gases under the same conditions of temperature and pressure contain an equal number of molecules. Its applications are:
- Determining Atomicity: It helps in determining the atomicity (number of atoms in a molecule) of gases.
- Gay-Lussac's Law Explanation: It helps to explain Gay-Lussac's law of combining volumes.
- Molecular Formula: It is used to determine the molecular formula of a gaseous compound.
- Molar Mass and Vapour Density: It helps in establishing the relationship between the molar mass of a gas and its vapour density. The relationship is: Molar Mass = 2 × Vapour Density.
23. a) Name the acid that renders aluminium passive. Why?
b) What is an Amalgam? Give an example.
a) Acid that renders aluminium passive:
- Acid: Dilute or concentrated Nitric acid ($HNO_3$).
- Reason: When aluminium reacts with nitric acid, it forms a thin, tough, and non-porous protective layer of aluminium oxide ($Al_2O_3$) on its surface. This oxide layer prevents the metal from further reaction with the acid, making the aluminium "passive".
b) Amalgam:
- Definition: An amalgam is an alloy of mercury with one or more other metals.
- Example: A common example is dental amalgam, which is an alloy of mercury with silver, tin, and copper, used for filling dental cavities. Another example is sodium amalgam ($Na-Hg$), used in chemistry as a reducing agent.
24. a) What is respiratory quotient?
b) Write a short note on mesophyll.
a) Respiratory Quotient (RQ):
The Respiratory Quotient is the ratio of the volume of carbon dioxide ($CO_2$) evolved to the volume of oxygen ($O_2$) consumed during respiration.
$$ RQ = \frac{\text{Volume of } CO_2 \text{ evolved}}{\text{Volume of } O_2 \text{ consumed}} $$
The value of RQ varies depending on the type of respiratory substrate used (e.g., for carbohydrates, RQ = 1; for fats, RQ < 1).
b) Mesophyll:
Mesophyll is the ground tissue of a leaf located between the upper and lower epidermis. It is the primary site of photosynthesis. In dicot leaves, it is differentiated into two distinct layers:
- Palisade Mesophyll: Located below the upper epidermis, it consists of elongated, compactly arranged cells rich in chloroplasts. It is the main site of photosynthesis.
- Spongy Mesophyll: Located below the palisade layer, it consists of irregularly shaped cells with large intercellular air spaces. These spaces facilitate the exchange of gases ($CO_2$, $O_2$, water vapour) within the leaf.
25. Calculate the mass of 2.24 L of SO₂ gas at S.T.P.
1. Calculate the molar mass of SO₂:
- Atomic mass of Sulphur (S) = 32 g/mol
- Atomic mass of Oxygen (O) = 16 g/mol
- Molar mass of SO₂ = 32 + 2(16) = 32 + 32 = 64 g/mol
2. Use the molar volume concept at S.T.P.:
At Standard Temperature and Pressure (S.T.P.), 1 mole of any ideal gas occupies a volume of 22.4 Litres.
This means: 22.4 L of SO₂ gas has a mass of 64 g.
3. Calculate the mass for the given volume:
We need to find the mass of 2.24 L of SO₂.
$$ \text{Mass} = \left( \frac{\text{Molar Mass}}{\text{Molar Volume}} \right) \times \text{Given Volume} $$
$$ \text{Mass} = \left( \frac{64 \text{ g}}{22.4 \text{ L}} \right) \times 2.24 \text{ L} $$
$$ \text{Mass} = 64 \times \frac{2.24}{22.4} $$
$$ \text{Mass} = 64 \times 0.1 = 6.4 \text{ g} $$
The mass of 2.24 L of SO₂ gas at S.T.P. is 6.4 grams.
26. a) i) What are the types of inertia? Give an example for each type. (5)
ii) State Rayleigh's law of scattering. (2)
a) i) Types of Inertia:
Inertia is the property of a body to resist any change in its state of rest or uniform motion. There are three types of inertia:
- Inertia of Rest: The inability of a body to change its state of rest by itself.
- Example: When a bus suddenly starts moving, passengers standing inside tend to fall backward. This is because their feet move with the bus, but the upper part of their body tries to remain at rest due to inertia.
- Inertia of Motion: The inability of a body to change its state of uniform motion by itself.
- Example: When a moving bus suddenly stops, passengers tend to fall forward. This is because their feet come to a stop with the bus, but the upper part of their body continues to move forward due to inertia of motion. An athlete running a race continues to run for some distance after crossing the finish line for the same reason.
- Inertia of Direction: The inability of a body to change its direction of motion by itself.
- Example: When a fast-moving car takes a sharp turn, the passengers are thrown outwards. This is because their body tries to continue moving in the original straight-line path due to inertia of direction.
ii) Rayleigh's Law of Scattering:
Rayleigh's law of scattering states that the amount of scattering of light is inversely proportional to the fourth power of its wavelength ($ \lambda $), provided the size of the scatterer is much smaller than the wavelength of light.
Mathematically: $$ \text{Amount of Scattering} \propto \frac{1}{\lambda^4} $$
b) i) Give the salient features of "Modern atomic theory". (5)
ii) Give any two examples for hetero diatomic molecules. (2)
b) i) Salient Features of Modern Atomic Theory:
- Atom is no longer indivisible: An atom is composed of subatomic particles like protons, neutrons, and electrons.
- Isotopes: Atoms of the same element can have different atomic masses. These are called isotopes (e.g., Carbon-12, Carbon-14).
- Isobars: Atoms of different elements can have the same atomic mass. These are called isobars (e.g., Argon-40, Calcium-40).
- Atoms are not always combined in simple whole-number ratios: In complex organic compounds and non-stoichiometric compounds, the ratio of atoms may not be simple (e.g., sucrose $C_{12}H_{22}O_{11}$).
- Atom is the smallest particle that takes part in a chemical reaction: While divisible, the atom remains the fundamental unit in chemical reactions.
- Mass can be converted into energy: According to Einstein's equation $E=mc^2$, the mass of an atom can be converted into energy, which is the principle of nuclear reactions. This means mass is not always conserved in nuclear reactions, but mass-energy is.
ii) Examples of Hetero Diatomic Molecules:
Hetero diatomic molecules are molecules composed of two different atoms. Two examples are:
- Hydrogen Chloride (HCl)
- Carbon Monoxide (CO)
27. a) Differentiate the following:
i) Monocot root and Dicot root (4)
ii) Aerobic and Anaerobic respiration (3)
a) i) Differentiation between Monocot Root and Dicot Root:
| Feature | Dicot Root | Monocot Root |
|---|---|---|
| Xylem Bundles | Tetrarch (four xylem bundles). | Polyarch (many xylem bundles, usually more than six). |
| Pith | Small or absent. | Large and well-developed at the center. |
| Cambium | Present during secondary growth. | Absent, so no secondary growth occurs. |
| Root System | Tap root system. | Fibrous root system. |
ii) Differentiation between Aerobic and Anaerobic Respiration:
| Feature | Aerobic Respiration | Anaerobic Respiration |
|---|---|---|
| Oxygen Requirement | Occurs in the presence of oxygen. | Occurs in the absence of oxygen. |
| Energy Production | Large amount of energy is released (36-38 ATP molecules). | Small amount of energy is released (2 ATP molecules). |
| End Products | Carbon dioxide ($CO_2$) and water ($H_2O$). | Ethyl alcohol and $CO_2$ (in yeast) or Lactic acid (in muscles). |
| Location | Cytoplasm and Mitochondria. | Only in the Cytoplasm. |
b) i) List out the parasitic adaptations in leech. (5)
ii) How is diastema formed in rabbit. (2)
b) i) Parasitic Adaptations in Leech:
The leech exhibits several adaptations for its parasitic (sanguivorous or blood-sucking) mode of life:
- Suckers: It has an anterior and a posterior sucker, which help it to attach firmly to the host's body.
- Jaws and Teeth: The mouth, located in the anterior sucker, is equipped with three jaws bearing tiny, sharp teeth. These create a painless, Y-shaped incision in the host's skin.
- Anticoagulant (Hirudin): Its salivary glands secrete hirudin, a powerful anticoagulant. This substance is injected into the wound to prevent blood from clotting, ensuring a continuous flow of blood.
- Pharynx: The muscular pharynx acts as a powerful pump to suck blood from the host.
- Crop: The crop is a large, extensible part of the alimentary canal with several chambers (caeca) for storing large amounts of ingested blood. This allows the leech to survive for months without another meal.
- Anaesthetic Saliva: The saliva also contains an anaesthetic substance, so the host often does not feel the bite.
ii) Formation of Diastema in Rabbit:
A diastema is a gap between the incisor teeth and the premolar teeth in the jaw of an animal. In a rabbit, this gap is formed due to the absence of canine teeth. Rabbits are herbivores, and their dentition is adapted for gnawing on vegetation with their sharp incisors and grinding it with their premolars and molars. They do not need canine teeth for tearing flesh, and this evolutionary absence creates the characteristic gap or diastema in their jaw.